class ChainPointV2(object):
def __init__(self, hash_type="sha256"):
self.hash_type = hash_type.lower()
self.mk = MerkleTools(hash_type)
'''Wraps merkletools method'''
def reset_tree(self):
self.mk.reset_tree()
'''Wraps merkletools method'''
def add_leaf(self, values, do_hash=False):
self.mk.add_leaf(values, do_hash)
'''Wraps merkletools method'''
def get_leaf(self, index):
return self.mk.get_leaf(index)
'''Wraps merkletools method'''
def get_leaf_count(self):
return self.mk.get_leaf_count()
'''Wraps merkletools method'''
def get_tree_ready_state(self):
return self.mk.get_tree_ready_state()
'''Wraps merkletools method'''
def make_tree(self):
self.mk.make_tree()
'''Wraps merkletools method'''
def get_merkle_root(self):
return self.mk.get_merkle_root()
'''Wraps merkletools method'''
def get_proof(self, index):
return self.mk.get_proof(index)
'''Wraps merkletools method'''
def validate_proof(self, proof, target_hash, merkle_root):
return self.mk.validate_proof(proof, target_hash, merkle_root)
def get_chainpoint_hash_type(self):
return CHAINPOINT_HASH_TYPES[self.hash_type]
'''
Returns the chainpoint v2 blockchain receipt for specific leaf
Currently only works for BTC anchors
'''
def get_receipt(self, index, btc_source_id):
if self.get_tree_ready_state():
return {
"@context": CHAINPOINT_CONTEXT,
"type": self.get_chainpoint_hash_type(),
"targetHash": self.get_leaf(index),
"merkleRoot": self.get_merkle_root(),
"proof": self.get_proof(index),
"anchors": [{
"type": "BTCOpReturn",
"sourceId": btc_source_id
}]
}
else:
return None
'''
Validates a chainpoint receipt. Currently only for BTC anchors
receipt is the chainpoint_proof metadata from the pdf file.
certificate_hash is the hash of the certificate after we removed the
chainpoint_proof metadata
issuer_identifier is a fixed 8 bytes issuer code that displays on the
blockchain
testnet specifies if testnet or mainnet was used
'''
# TODO consider using exceptions instead of (bool, text) tuples; this is
# really only needed for valid but soon to expire
def validate_receipt(self,
receipt,
certificate_hash,
issuer_identifier='',
testnet=False):
# check context and hash type
if (receipt['@context'].lower() != CHAINPOINT_CONTEXT):
return False, "wrong chainpoint context"
if (receipt['type'] not in CHAINPOINT_HASH_TYPES.values()):
return False, "type not in CHAINPOINT_HASH_TYPES"
target_hash = receipt['targetHash']
merkle_root = receipt['merkleRoot']
proof = receipt['proof']
# validate actual hash
if target_hash.lower() != certificate_hash.lower():
return False, "certificate hash is different than the one in receipt"
# validate merkle proof
if (not self.validate_proof(proof, target_hash, merkle_root)):
return False, "certificate's hash is not in merkle root"
txid = self.get_txid_from_receipt(receipt)
# validate anchor
op_return_hex = network_utils.get_op_return_hex_from_blockchain(
txid, testnet)
# ignore issuer_identifier for now (it is string in CRED but used to be
# hex so we need a smart way to get it) -- TODO: obsolete it !!!
#issuer_id_hex = utils.text_to_hex(issuer_identifier)
# if op_return starts with CRED it is using the meta-protocol
op_dict = cred_protocol.parse_op_return_hex(op_return_hex)
if op_dict:
version_hex = op_dict['version']
command_hex = op_dict['cmd']
# could check if it is equal to issuer_id_hex
issuer_hex = op_dict['data']['issuer_identifier']
# get merkle root
hash_hex = op_dict['data']['merkle_root']
# if issue with expiry get expiry date
if command_hex == cred_protocol.hex_op('op_issue_abs_expiry'):
expiry_hex = op_return_hex[96:116]
else:
expiry_hex = None
#print(version_hex)
#print(command_hex)
#print(issuer_hex)
#print(hash_hex)
#print(merkle_root.lower())
# otherwise op_return should be fixed to 7 bytes or 14 hex chars (old prefix method)
else:
ignore_hex_chars = 14
hash_hex = op_return_hex[ignore_hex_chars:]
if (not merkle_root.lower() == hash_hex.lower()):
return False, "certificate's merkle root is different than the one in the blockchain"
# only for CRED protocol certificates check expiration date if
# issued with expiry date
if op_dict and expiry_hex:
expiry = utils.hex_to_int(expiry_hex)
if expiry > int(time.time()):
return True, "valid until: " + str(expiry)
else:
return False, "certificate expired at: " + str(expiry)
return True, None
# def get_op_return_hex_from_blockchain(self, txid, testnet):
# # uses blockcypher API for now -- TODO: expand to consult multiple services
# if testnet:
# blockcypher_url = "https://api.blockcypher.com/v1/btc/test3/txs/" + txid
# else:
# blockcypher_url = "https://api.blockcypher.com/v1/btc/main/txs/" + txid
#
# response = requests.get(blockcypher_url).json()
# outputs = response['outputs']
# hash_hex = ""
# for o in outputs:
# script = o['script']
# if script.startswith('6a'):
# # when > 75 op_pushdata1 (4c) is used before length
# if script.startswith('6a4c'):
# # 2 for 1 byte op_return + 2 for 1 byte op_pushdata1 + 2 for 1 byte data length
# ignore_hex_chars = 6
# else:
# # 2 for 1 byte op_return + 2 for 1 byte data length
# ignore_hex_chars = 4
#
# hash_hex = script[ignore_hex_chars:]
# break
# return hash_hex
def get_txid_from_receipt(self, receipt):
# get anchor
# TODO currently gets only the first valid (BTC) anchor
anchors = receipt['anchors']
txid = ''
for a in anchors:
if a['type'] in CHAINPOINT_ANCHOR_TYPES.values():
txid = a['sourceId']
break
return txid
class ChainPointV2(object):
def __init__(self, hash_type="sha256"):
self.hash_type = hash_type.lower()
self.mk = MerkleTools(hash_type)
'''Wraps merkletools method'''
def reset_tree(self):
self.mk.reset_tree()
'''Wraps merkletools method'''
def add_leaf(self, values, do_hash=False):
self.mk.add_leaf(values, do_hash)
'''Wraps merkletools method'''
def get_leaf(self, index):
return self.mk.get_leaf(index)
'''Wraps merkletools method'''
def get_leaf_count(self):
return self.mk.get_leaf_count()
'''Wraps merkletools method'''
def get_tree_ready_state(self):
return self.mk.get_tree_ready_state()
'''Wraps merkletools method'''
def make_tree(self):
self.mk.make_tree()
'''Wraps merkletools method'''
def get_merkle_root(self):
return self.mk.get_merkle_root()
'''Wraps merkletools method'''
def get_proof(self, index):
return self.mk.get_proof(index)
'''Wraps merkletools method'''
def validate_proof(self, proof, target_hash, merkle_root):
return self.mk.validate_proof(proof, target_hash, merkle_root)
def get_chainpoint_hash_type(self):
return CHAINPOINT_HASH_TYPES[self.hash_type]
'''
Returns the chainpoint v2 blockchain receipt for specific leaf
Currently only works for bitcoin and litecoin anchors
'''
def get_receipt(self, index, source_id, chain, testnet):
chain_type = utils.get_chain_type(chain, testnet)
if(chain_type is not None and self.get_tree_ready_state()):
return {
"@context": CHAINPOINT_CONTEXT,
"type": self.get_chainpoint_hash_type(),
"targetHash": self.get_leaf(index),
"merkleRoot": self.get_merkle_root(),
"proof": self.get_proof(index),
"anchors": [
{
"type": CHAINPOINT_ANCHOR_TYPES[chain_type],
"sourceId": source_id
}
]
}
else:
return None
'''
Validates a chainpoint receipt. Currently for BTC and LTC anchors
receipt is the chainpoint_proof metadata from the pdf file.
certificate_hash is the hash of the certificate after we removed the
chainpoint_proof metadata
issuer_identifier is a fixed 8 bytes issuer code that displays on the
blockchain
'''
# TODO consider using exceptions instead of (bool, text) tuples; this is
# really only needed for valid but soon to expire
def validate_receipt(self, receipt, op_return_hex, certificate_hash, issuer_identifier=''):
# check context and hash type
if(receipt['@context'].lower() != CHAINPOINT_CONTEXT):
return False, "wrong chainpoint context"
if(receipt['type'] not in CHAINPOINT_HASH_TYPES.values()):
return False, "chainpoint type not in CHAINPOINT_HASH_TYPES"
# currently only one anchor at a time is allowed; thus 0
if(receipt['anchors'][0]['type'] not in CHAINPOINT_ANCHOR_TYPES.values()):
return False, "anchor type not in CHAINPOINT_ANCHOR_TYPES"
target_hash = receipt['targetHash']
merkle_root = receipt['merkleRoot']
proof = receipt['proof']
# validate actual hash
if target_hash.lower() != certificate_hash.lower():
return False, "certificate hash is different than the one in receipt"
# validate merkle proof
if(not self.validate_proof(proof, target_hash, merkle_root)):
return False, "certificate's hash is not in merkle root"
# ignore issuer_identifier for now (it is string in CRED but used to be
# hex so we need a smart way to get it) -- TODO: obsolete it !!!
#issuer_id_hex = utils.text_to_hex(issuer_identifier)
# if op_return starts with CRED it is using the meta-protocol
op_dict = cred_protocol.parse_op_return_hex(op_return_hex)
if op_dict:
version_hex = op_dict['version']
command_hex = op_dict['cmd']
# could check if it is equal to issuer_id_hex
issuer_hex = op_dict['data']['issuer_identifier']
# get merkle root
hash_hex = op_dict['data']['merkle_root']
# if issue with expiry get expiry date
if command_hex == cred_protocol.hex_op('op_issue_abs_expiry'):
expiry_hex = op_return_hex[96:116]
else:
expiry_hex = None
#print(version_hex)
#print(command_hex)
#print(issuer_hex)
#print(hash_hex)
#print(merkle_root.lower())
# otherwise op_return should be fixed to 7 bytes or 14 hex chars (old prefix method)
else:
ignore_hex_chars = 14
hash_hex = op_return_hex[ignore_hex_chars:]
if(not merkle_root.lower() == hash_hex.lower()):
return False, "certificate's merkle root is different than the one in the blockchain"
# only for CRED protocol certificates check expiration date if
# issued with expiry date
if op_dict and expiry_hex:
expiry = utils.hex_to_int(expiry_hex)
if expiry > int(time.time()):
return True, "valid until: " + str(expiry)
else:
return False, "certificate expired at: " + str(expiry)
return True, None
# TODO: DELETE - NOT USED ANYWHERE !!
def get_chain_testnet_txid_from_receipt(self, receipt):
# get anchor
# TODO currently gets only the first valid anchor
anchors = receipt['anchors']
chain = ''
testnet = False
txid = ''
for a in anchors:
if a['type'] in CHAINPOINT_ANCHOR_TYPES.values():
if(a['type'] == 'BTCOpReturn'):
chain = 'bitcoin'
testnet = False
elif(a['type'] == 'LTCOpReturn'):
chain = 'litecoin'
testnet = False
elif(a['type'] == 'BTCTestnetOpReturn'):
chain = 'bitcoin'
testnet = True
elif(a['type'] == 'LTCTestnetOpReturn'):
chain = 'litecoin'
testnet = True
txid = a['sourceId']
break
return chain, testnet, txid
def test_add_leaf():
mt = MerkleTools()
mt.add_leaf("tierion")
mt.add_leaf(["bitcoin", "blockchain"])
assert mt.get_leaf_count() == 3
assert mt.is_ready is False
def test_add_leaf():
mt = MerkleTools()
mt.add_leaf("tierion", do_hash=True)
mt.add_leaf(["bitcoin", "blockchain"], do_hash=True)
assert mt.get_leaf_count() == 3
assert mt.is_ready == False
import merkletools
from merkletools import MerkleTools
from hashlib import sha256
import json
myMerkleT = MerkleTools(hash_type="sha256") # This will make use of SHA256
myMerkleT.add_leaf(["Security", "Room14", "Professor"], True) # My first leaves.
myMerkleT.add_leaf(["Room12", "blockchain", "Python"], True) # This adds three leaves to the Tree.
myMerkleT.add_leaf(["Name:Justice", "Course:Computer Science"], True) # Another three leaves.
myMerkleT.make_tree() # Creating the Merkle Tree.
print('')
numberOfLeaves = myMerkleT.get_leaf_count()
print("The number of leaves of this tree is: ", numberOfLeaves)
print("root:", myMerkleT.get_merkle_root())
print("The value at leaf 2 is: ", myMerkleT.get_leaf(2))
print("The array of hash objects for the leaf at index 2 is: ", myMerkleT.get_proof(2))
print('')
print('************************ Merkle Proof ****************************')
print(myMerkleT.validate_proof(myMerkleT.get_proof(2), myMerkleT.get_leaf(2), myMerkleT.get_merkle_root())) # True
print('************************ Merkle Proof ****************************')
TestData = ["My Professor is helping me to learn well."]
from merkletools import MerkleTools
mt = MerkleTools()
mt.add_leaf("tierion", True)
mt.add_leaf(["bitcoin", "blockchain"], True)
mt.make_tree()
print mt.get_leaf_count()
print "root:", mt.get_merkle_root(
) # root: '777765f15d171871b00034ee55e48ffdf76afbc44ed0bcff5c82f31351d333c2ed1'
print mt.get_proof(
1
) # [{left: '2da7240f6c88536be72abe9f04e454c6478ee29709fc3729ddfb942f804fbf08'},
# {right: 'ef7797e13d3a75526946a3bcf00daec9fc9c9c4d51ddc7cc5df888f74dd434d1'}]
print mt.validate_proof(mt.get_proof(1), mt.get_leaf(1), mt.get_merkle_root())
